Just had a problem with Webmin reporting that packages were updated and need to be installed. When going through the install process it seemed that there were some packages still to be installed. Going back through the update process shows no packages updated...
After a while of this happening, new packages available then install missing some I found that some security patches were being missed by Webmin. Doing an update from command line seems to have fixed the problem:
$ sudo apt-get upgrade[/geshifilter-pre]